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Lipid changes within the epidermis of living skin equivalents observed across a time-course by MALDI-MS imaging and profiling.

Mitchell CA, Long H, Donaldson M, Francese S, Clench MR - Lipids Health Dis (2015)

Bottom Line: In particular development of an epidermal layer was observable as a compaction of the distribution of phosphatidylcholine species.MSI can be used to study changes in lipid composition in LSE.Determination of the changes in lipid distribution during the maturation of the LSE will assist in the identification of treatment responses in future investigations.

View Article: PubMed Central - PubMed

Affiliation: Biomedical Research Centre, Sheffield Hallam University, Howard Street, Sheffield, S1 1WB, UK. c.mitchell@surrey.ac.uk.

ABSTRACT

Background: Mass spectrometry imaging (MSI) is a powerful tool for the study of intact tissue sections. Here, its application to the study of the distribution of lipids in sections of reconstructed living skin equivalents during their development and maturation is described.

Methods: Living skin equivalent (LSE) samples were obtained at 14 days development, re-suspended in maintenance medium and incubated for 24 h after delivery. The medium was then changed, the LSE re-incubated and samples taken at 4, 6 and 24 h time points. Mass spectra and mass spectral images were recorded from 12 μm sections of the LSE taken at each time point for comparison using matrix assisted laser desorption ionisation mass spectrometry.

Results: A large number of lipid species were identified in the LSE via accurate mass-measurement MS and MSMS experiments carried out directly on the tissue sections. MS images acquired at a spatial resolution of 50 μm × 50 μm showed the distribution of identified lipids within the developing LSE and changes in their distribution with time. In particular development of an epidermal layer was observable as a compaction of the distribution of phosphatidylcholine species.

Conclusions: MSI can be used to study changes in lipid composition in LSE. Determination of the changes in lipid distribution during the maturation of the LSE will assist in the identification of treatment responses in future investigations.

No MeSH data available.


Positive ion MALDI Mass spectrum of a LSE (24 h incubation) across the full thickness of the tissue, using α-CHCA/ANI as a matrix
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Fig1: Positive ion MALDI Mass spectrum of a LSE (24 h incubation) across the full thickness of the tissue, using α-CHCA/ANI as a matrix

Mentions: A representative mass spectrum obtained from the untreated LSE 24 h incubation sample group is shown in Fig. 1. The spectrum shows the large number of lipid species present within the sample. Additional file 1: Table S1 shows the results of the database search of the accurate masses (5 ppm) of detected peaks. The lipid groups identified and reported in the table include free-fatty acids, glycerophosphonoethanolamines, glycerophosphocholine, sphingolipids and triacylglycerols. Phosphatydlcholine (PC), sphingomyelin (SM) and lyso phosphatydlcholine (LPC) species appear to be most dominant in the average spectra. PC lipids were particularly populated between the m/z 670 and 900 range with intensity counts approximately 4 times greater than the other low abundant signals at the lower mass ranges. Many of the detected compounds including PC 34:2 (m/z 780.5 M + Na+), PC 36:2 (m/z 786.6 M + H), PC 36:1 or PE 39:1 (m/z 810.5 M + Na+) were previously identified in ex-vivo human skin also [10]. The dominance of phospholipids in the spectra is probably due to their biological abundance in tissue; the fixed positive charge from the choline head-group allows PC species to have strong ionisation efficiencies.Fig. 1


Lipid changes within the epidermis of living skin equivalents observed across a time-course by MALDI-MS imaging and profiling.

Mitchell CA, Long H, Donaldson M, Francese S, Clench MR - Lipids Health Dis (2015)

Positive ion MALDI Mass spectrum of a LSE (24 h incubation) across the full thickness of the tissue, using α-CHCA/ANI as a matrix
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4525729&req=5

Fig1: Positive ion MALDI Mass spectrum of a LSE (24 h incubation) across the full thickness of the tissue, using α-CHCA/ANI as a matrix
Mentions: A representative mass spectrum obtained from the untreated LSE 24 h incubation sample group is shown in Fig. 1. The spectrum shows the large number of lipid species present within the sample. Additional file 1: Table S1 shows the results of the database search of the accurate masses (5 ppm) of detected peaks. The lipid groups identified and reported in the table include free-fatty acids, glycerophosphonoethanolamines, glycerophosphocholine, sphingolipids and triacylglycerols. Phosphatydlcholine (PC), sphingomyelin (SM) and lyso phosphatydlcholine (LPC) species appear to be most dominant in the average spectra. PC lipids were particularly populated between the m/z 670 and 900 range with intensity counts approximately 4 times greater than the other low abundant signals at the lower mass ranges. Many of the detected compounds including PC 34:2 (m/z 780.5 M + Na+), PC 36:2 (m/z 786.6 M + H), PC 36:1 or PE 39:1 (m/z 810.5 M + Na+) were previously identified in ex-vivo human skin also [10]. The dominance of phospholipids in the spectra is probably due to their biological abundance in tissue; the fixed positive charge from the choline head-group allows PC species to have strong ionisation efficiencies.Fig. 1

Bottom Line: In particular development of an epidermal layer was observable as a compaction of the distribution of phosphatidylcholine species.MSI can be used to study changes in lipid composition in LSE.Determination of the changes in lipid distribution during the maturation of the LSE will assist in the identification of treatment responses in future investigations.

View Article: PubMed Central - PubMed

Affiliation: Biomedical Research Centre, Sheffield Hallam University, Howard Street, Sheffield, S1 1WB, UK. c.mitchell@surrey.ac.uk.

ABSTRACT

Background: Mass spectrometry imaging (MSI) is a powerful tool for the study of intact tissue sections. Here, its application to the study of the distribution of lipids in sections of reconstructed living skin equivalents during their development and maturation is described.

Methods: Living skin equivalent (LSE) samples were obtained at 14 days development, re-suspended in maintenance medium and incubated for 24 h after delivery. The medium was then changed, the LSE re-incubated and samples taken at 4, 6 and 24 h time points. Mass spectra and mass spectral images were recorded from 12 μm sections of the LSE taken at each time point for comparison using matrix assisted laser desorption ionisation mass spectrometry.

Results: A large number of lipid species were identified in the LSE via accurate mass-measurement MS and MSMS experiments carried out directly on the tissue sections. MS images acquired at a spatial resolution of 50 μm × 50 μm showed the distribution of identified lipids within the developing LSE and changes in their distribution with time. In particular development of an epidermal layer was observable as a compaction of the distribution of phosphatidylcholine species.

Conclusions: MSI can be used to study changes in lipid composition in LSE. Determination of the changes in lipid distribution during the maturation of the LSE will assist in the identification of treatment responses in future investigations.

No MeSH data available.